Operation CASTLE was a six-detonation test series held at the Atomic Energy Commission's (AEC) Pacific Proving Ground in the Spring of 1954. This test series, principally conducted at the Enewetak and Bikini Atolls in the northwestern Marshall Islands, provided proof tests of large-yield thermonuclear, or hydrogen, devices.

CASTLE represented the end of a drive for a workable thermonuclear weapon and the beginning of the refinement of large-H-bombs into smaller and more efficient weapons. After CASTLE, the U.S. could choose in a range of small tactical weapons to large strategic weapons. From this point, weapons development programs concentrated on producing bombs of specific nuclear weapons effects -- heat, blast, and radiation.

The Bravo event of the CASTLE series yielded 15 megatons, unexpectedly the most ever exploded in atmospheric testing by the U.S.. A scientific miscalculation based on a then-unknown "tritium fusion bonus" of highly enriched lithium-6 contributing the the detonation yield caused the yield to be about two and a half times of that what was expected.

Reports indicate that Bravo was the single worst incident of fallout exposure in all of the U.S. atmospheric testing program. Despite winds in an acceptable flow zone, the greatly unexpected yield caused a much larger mushroom than originally calculated, causing a much wider and massive accumulation path of fallout danger. Fallout was scattered over more than 5,000 square miles of ocean and islands, resulting in the contamination and exposure of military, civilian U.S. personnel working on the shot, and people of the islands who were earlier moved to a supposedly "safe" island but received large amounts of radiation. Acute radiation effects were observed among some of these people.

The supreme commander of Joint Task Force 7 was Major General Percy Clarkson, who gave this report to top secret oversight committees of U.S. Congress. General Clarkson was the U.S. Army's 33rd Division commander (October 1943 - November 1945) in the raging battles of the Philippines during the Second World War.

This film was originally created as a film archive of the Armed Forces Special Weapons Project (AFSWP), the Atomic Energy Commission (AEC) -- now named the U.S. Department of Energy -- and as a formal technical report to top secret oversight committees of U.S. Congress. The specific purpose of this film was to illustrate important results of these massive nuclear detonations, particularly tuned to applications, knowledge, and interests of the United States military.

AFSWP was the Pentagon department overseeing the U.S. military's role in the development of nuclear weapons.

This film was not sanitized/edited for declassification until years after the end of the Cold War. The declassification tags are at the beginning of the film, to document that this film has been carefully screened to remove data considered secret to national defense experts. If the sound cuts out at times into silence, or the view blackens with audio playing, these are not flaws in the film, but a censoring blocks of secret data edited out of the film.

The license question needs to be answered. I can find no basis for this video being other than public domain. It was produced by a publicly funded organization for a public organization about a publicly funded activity. It has been censored and released to the public. How does the so-called license holder justify limitations of use in any way? Answer the question or correct, by removing, the license restriction.

What is the basis for this license claim? The Trinity and Crossroads film reports are public domain. How is this Castle report distinguished from those reports?

Credits

The license holder of this film insists that any site (or individuals) linking or independently displaying through any Internet protocol to this film, to visibly, clearly and fully credit in text this organization ["Nuclear Weapons Vault"] on any pages linked, for providing this film: "Provided by the Nuclear Weapons Vault" This license does NOT allow derivations or alterations of this film. This license does NOT allow use of any portion of this film as part of other films, and this license does NOT allow artistic or technical alterations or commercial uses. This license does NOT allow this film to be displayed other than its entirety in the final forms of the files posted at Archive.org.